Computer modeling of the spatial resolution properties of a dedicated breast CT system

Kai Yang, Alexander L C Kwan, John M Boone

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

Computer simulation methods were used to evaluate the spatial resolution properties of a dedicated cone-beam breast CT system. x-ray projection data of a 70 μm nickel-chromium wire were simulated. The modulation transfer function (MTF) was calculated from the reconstructed axial images at different radial positions from the isocenter to study the spatial dependency of the spatial resolution of the breast CT scanner. The MTF was also calculated in both the radial and azimuthal directions. Subcomponents of the cone beam CT system that affect the MTF were modeled in the computer simulation in a serial manner, including the x-ray focal spot distribution, gantry rotation under the condition of continuous fluoroscopy, detector lag, and detector spatial resolution. Comparison between the computer simulated and physically measured MTF values demonstrates reasonable accuracy in the simulation process, with a small systematic difference (∼9.5±6.4% difference, due to unavoidable uncertainties from physical measurement and system calibration). The intrinsic resolution in the radial direction determined by simulation was about 2.0 mm-1 uniformly through the field of view. The intrinsic resolution in the azimuthal direction degrades from 2.0 mm-1 at the isocenter to 1.0 mm-1 at the periphery with 76.9 mm from the isocenter. The results elucidate the intrinsic spatial resolution properties of the prototype breast CT system, and suggest ways in which spatial resolution can be improved with system modification.

Original languageEnglish (US)
Pages (from-to)2059-2069
Number of pages11
JournalMedical Physics
Volume34
Issue number6
DOIs
StatePublished - 2007

Keywords

  • Breast cancer
  • Computer simulation
  • Cone-beam CT
  • Image quality
  • MTF
  • Spatial resolution

ASJC Scopus subject areas

  • Biophysics

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